Mold forming often in Walkin Refrigerator

Has anyone an idea of the reason Mold would be forming just about everywhere inside the cooler in just “TWO WEEKS” time in our 8 x 12 walk-in cooler? Having this same cooler since 2000 and the only change has been a new evaporator was installed a few years ago. Although that seems to be when it started forming quicker than before. Prior, It would take 6mos to a yr or more of a surface not cleaned to form mold on it. All penetrations are sealed up and door gaskets are not leaking. But it must have something to do with the humidity because its worse in the summer.

Yeah, it seems the humidity level in the walk in is higher than it used to be. The evaporator dehumidifies the air in addition to cooling it. Could your evaporator fan be running backwards? It should pull air across the coils towards the fan. The water that is removed drips to a pan that then drains out a tube. Is the pan tilted the wrong way and pooling before it finally drains? A partially clogged drain can also cause water to pool in the catch pan. Blow the tube out with compressed air to unclog it . This might cause higher humidity level. Is the tube leaking before it exits the walk in. Does the new evaporator run all the time or cycle on and off with the compressor?
Those are a few questions I’d ask about the evaporator.
A change of use can also cause issues. For example, are steaming hot liquids cooled in the walk in or first bench cooled?